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Integrating machine learning and CALPHAD method for exploring low-modulus near-β-Ti alloys

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Rare Metals 2024年第1期43卷 309-323页

作者： Hao zou Yue-Yan Tian Li-Gang Zhang ren-Hao Xue Zi-Xuan deng Ming-Ming lu jian-Xin Wang Li-Bin Liu School of Computer Science and Engineering Central South UniversityChangsha 410083China School of Materials Science and Engineering Central South UniversityChangsha 410083China State Key Laboratory of Powder Metallurgy Central South UniversityChangsha 410083China

Traditional theoretical and empirical calculation methods can guide the design of β-and metastable β-alloys for bio-titanium. However, it is still difficult to obtain novel near-β-Ti alloys with low modulus. This study developed a method that combines machine learning with calculation of phase diagrams(CALPHAD) to facilitate the design of near-β-Ti alloys. An elastic modulus database of Ti–Nb–Zr–Mo–Ta–Sn system was constructed first, and then three features(the electron to atom ratio, mean absolute deviation of atom mass, and mean electronegativity) were selected as the key factors of modulus by performing a three-step feature selection. With these features, a highly accurate model was built for predicting the modulus of near-β-Ti alloys. To further ensure the accuracy of modulus prediction, machine learning with the elastic constants calculated was leveraged by CALPHAD database. The root mean square error of the well-trained model can be as low as 6.75 GPa. Guided by the prediction of machine learning and CALPHAD, three novel near-β-Ti alloys with elastic modulus below 50 GPa were successfully designed in this study. The best candidate alloy(Ti–26Nb–4Zr–4Sn–1Mo–Ta) exhibits an ultra-low modulus(36.6 GPa) after cold rolling with a thickness reduction of 20%. Our method can greatly save time and resources in the development of novel Ti alloys, and experimental verifications have demonstrated the reliability of this method.

关键词： Near-β-Ti alloy Machine learning Calculation of phase diagram Low-modulus alloy Feature selection

Numerical simulation of three-dimensional wake transition

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Numerical simulation of three-dimensional wake transition

NUMERICAL SOluTION OF 2-D INCOMPRESSIBLE VISCOUS FLOW WITH HIGH ORDER COMPACT SCHEME USING DOMAIN DECOMPOSITION AND MATCHED METHOD

第十届全国分离流、旋涡和流动控制会议

作者： deng jian~(1)), ren An-lu, zou jian-feng (Department of Mechanics, Zhejiang University, Hangzhou 310027, China)

The studies concerning the wake transition regime of the flow around a circular cylinder become hot these years. Many experiments have been made for this problem but no accurate three-dimensional numerical simulations have hitherto been made. In this paper, a parallel procedure was developed to simulate the three-dimensional Navier-Stokes equations on an SGI Origin3900 machine. Two different parallel strategies on this application were analyzed about their efficiency. The critical Reynolds number of 195 is found. and the wake flow below this Reynolds number is pure two-dimensional. When the Reynolds number go beyond this critical point, the wake flow becomes instable to three-dimensional small disturb. The transition regime involves two modes of small-scale three-dimensional instability (modes A an B), depending on the regime of Reynolds number (Re). It is found that the two different modes A and B scales on different physical features of the flow, and many other important questions are addressed in this paper.

关键词： : three-dimensional Navier-Stokes equations, three-dimensional instability, wake transition. parallel computing

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Journal of Hydrodynamics 2001年第4期13卷 79-82页

作者： ren, An-lu lu, Xiao-Dong zou, jian-feng Zhou, Yong-Xia Dept. of Mech. Zhejiang Univ. Hangzhou 310027 China

This paper presents a high-accuracy method for solving 2-D incompressible viscous N-S equations in tensor forms. A domain decomposition method was used to divide the computational domain into several regular blocks with the overlapping grid in order to transfer data between sub-domains and to remove numerical singularity caused by domain decomposition. Using the method and algorithm presented above, the flow passing an ellipse was computed and the formation and evolution of the vortex shedding was successfully simulated.

关键词： Computational fluid dynamics Computational methods Incompressible flow Navier Stokes equations

BLOCK ITERATIVE METHODS FOR LINEAR ALGEBRAIC EQUATION AND DOMAIN DECOMPOSITION METHOD FOR INCOMPRESSIBLE VISCOUS FLOW

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Journal of Hydrodynamics 2002年第4期14卷 73-80页

作者： ren, An-lu zou, jian-feng Zhou, Yong-Xia Li, Guang-Wang Dept. of Mech. Zhejiang Univ. Hangzhou 310027 China

It was proved numerically that the Domain Decomposition Method CDDM) with one layer overlapping grids is identical to the block iterative method of linear algebra equations. The results obtained by using DDM could be in reasonable agreement with the results of full-domain simulation. With the three dimensional solver developed by the authors, the flow field in a pipe was simulated by using the full-domain DDM with one layer overlapping grids and with patched grids respectively. Both of the two cases led to the convergent solution. Further research shows the superiority of the DDM with one layer overlapping grids to the DDM with patched grids. A comparison between the numerical results obtained by the authors and the experimental results given by Enayet[3] shows that the numerical results are reasonable.

关键词： Computational fluid dynamics Computer simulation Iterative methods Linear equations Viscous flow

A comparison between novel Gd_(2)Zr_(2)O_(7)and Gd_(2)Zr_(2)O_(7)/YSZ thermal barrier coatings fabricated by plasma spray-physical vapor deposition

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Rare Metals 2021年第8期40卷 2244-2253页

作者： ren-Bo Zhu jian-Peng zou Jie Mao Zi-Qian deng Xiao-feng Zhang Chun-Ming deng Min Liu School of Materials Science and Engineering University of New South WalesSydneyNSW2052Australia State Key Laboratory of Powder Metallurgy Central South UniversityChangsha410083China National Engineering Laboratory for Modern Materials Surface Engineering Technology and Key Laboratory of Guangdong for Modern Surface Engineering Technology Guangdong Institute of New MaterialsGuangzhou510651China

Spherical Gd_(2)Zr_(2)O_(7)hollow powders with a mean size of 8.8μm were fabricated as feedstock for thermal barrier coatings(TBCs)by *** single-ceramic-layer(SCL)Gd_(2)Zr_(2)O_(7)TBCs and double-ceramic-layer(DCL)Gd_(2)Zr_(2)O_(7)/YSZ TBCs with quasicolumnar structure were successfully fabricated by plasma spray-physical vapor deposition(PS-PVD).Tensile and water-quenching tests were applied to evaluate TBCs *** results show that adhesion strength of SCL Gd_(2)Zr_(2)O_(7)TBCs and DCL Gd_(2)Zr_(2)O_(7)/YSZ TBCs is36.5 MPa and 15.4 MPa,*** delamination of SCL Gd_(2)Zr_(2)O_(7)TBCs and DCL Gd_(2)Zr_(2)O_(7)/YSZ TBCs in the tensile test takes place at the middle and bottom of Gd_(2)Zr_(2)O_(7)layer,respectively,due to relatively lower fracture toughness of Gd_(2)Zr_(2)O_(7)*** 40 cycles of water-quenching test,DCL Gd_(2)Zr_(2)O_(7)/YSZ TBC surface keeps relatively intact,while SCL Gd_(2)Zr_(2)O_(7)TBC surface shows 20%visible destroyed regions,which demonstrates that DCL Gd_(2)Zr_(2)O_(7)/YSZ TBCs have a better thermal shock resistance than SCL Gd_(2)Zr_(2)O_(7)*** cracks in the SCL system propagate near thermally grown oxide(TGO)due to thermal mismatch and TGO growing stress,while cracks in the DCL system propagate in the Gd_(2)Zr_(2)O_(7)layer due to its relatively lower fracture toughness.

关键词： Plasma spray-physical vapor deposition Thermal barrier coatings Gd_(2)Zr_(2)O_(7) Thermal shock resistance Adhesion strength

NUMERICAL STUDY OF FLOW PAST AN AXISYMMETRIC BODY WITH A RING WING AT VARIOUS ATTACK ANGLES

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Journal of Hydrodynamics 2003年第5期15卷 49-53页

作者： ren An lu, zou jian feng, Dai Zhi qian Department of Mechanics, Zhejiang University, 310027, China, Dept. of Mech. Zhejiang Univ. Zhejiang 310027 China

The laminar and turbulent flows past an axi-symmetric body with a ring wingwere investigated numerically at various attack angles (0°-20°) for the Reynolds numbers rangingfrom 10~3 to 10~7. The DDM (Domain Decomposition Method) with the Schwarz iterative method based onfinite difference approximation was applied to simulate this problem. The primitive variableformulation was used for the solution of the incompressible Navier-Stoke equations. The velocityfield was calculated from the unsteady momentum equation by marching in time. The continuityequation was replaced by a Poisson-type equation for the pressure with the Neumann boundaryconditions. The Baldwin-Lomax model was adopted to simulate turbulence effect. The leap frogimplicit iterative method was used for the time difference approximations. The computed pressure atthe front stagnation point is found to have a small deviation, less than 10%, from the theoreticalvalue. The outlet flux has a loss about 5%. The lift coefficients increase linearly with the attackangle, but for attack angles greater than 15° the lift coefficients show mild decrease. Thefriction drag coefficients are insensitive to the attack angles, but the pressure drag coefficientsincrease markedly with the attack angles. In addition, complex flow patterns are revealed within thevicinity of the ring wing.

关键词： an axisymmetric body domain decomposition method (DDM) baldwin-lomax model non-staggered grid

Searching for^(76)Ge neutrinoless double beta decay with the CDEX-1B experiment

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Chinese Physics C 2024年第10期48卷 11-22页

作者： Bing-Tao Zhang Jun-Zheng Wang Li-Tao Yang Qian Yue Ke-Jun Kang Yuan-Jing Li Hai-Peng An C.Greeshma jian-Ping Chang Yun-Huan Chen jian-Ping Cheng Wen-Han Dai Zhi deng Chang-Hao Fang Xin-Ping Geng Hui Gong Qiu-Ju Guo Xu-Yuan Guo Li He Sheng-Ming He Jin-Wei Hu Han-Xiong Huang Tu-Chen Huang Hai-Tao Jia Xi jiang S.Karmakar Hao-Bin Li jian-Min Li Jin Li Qian-Yun Li ren-Ming-Jie Li Xue-Qian Li Yu-Lan Li Yi-Fan Liang Bin Liao Fong-Kay Lin Shin-Ted Lin Jia-Xuan Liu Shu-Kui Liu Yan-Dong Liu Yu Liu Yuan-Yuan Liu Zhong-Zhi Liu Hao Ma Yu-Cai Mao Qi-Yuan Nie Jin-Hua Ning Hui Pan Ning-Chun Qi Jie ren Xi-Chao Ruan Ze She Manoj Kumar Singh Tian-Xi Sun Chang-jian Tang Wei-You Tang Yang Tian Guang-Fu Wang Li Wang Qing Wang Yu-feng Wang Yun-Xiang Wang Henry-Tsz-King Wong Shi-Yong Wu Yu-Cheng Wu Hao-Yang Xing Rui Xu Yin Xu Tao Xue Yu-lu Yan Nan Yi Chun-Xu Yu Hai-Jun Yu jian-feng Yue Ming Zeng Zhi Zeng feng-Shou Zhang Lei Zhang Zhen-Hua Zhang Zhen-Yu Zhang Kang-Kang Zhao Ming-Gang Zhao Ji-Fang Zhou Zu-Ying Zhou Jing-Jun Zhou Key Laboratory of Particle and Radiation Imaging(Ministry of Education)and Department of Engineering Physics Tsinghua UniversityBeijing 100084 Department of Physics Tsinghua UniversityBeijing 100084 Institute of Physics Academia SinicaTaipei 11529 NUCTECH Company Beijing 100084 YaLong River Hydropower Development Company Chengdu 610051 College of Nuclear Science and Technology Beijing Normal UniversityBeijing 100875 College of Physics Sichuan UniversityChengdu 610065 School of Physics Peking UniversityBeijing 100871 Department of Nuclear Physics China Institute of Atomic EnergyBeijing 102413 Sino-French Institute of Nuclear and Technology Sun Yat-sen UniversityZhuhai 519082 School of Physics Nankai UniversityTianjin 300071 Department of Physics Banaras Hindu UniversityVaranasi 221005 Department of Physics Beijing Normal UniversityBeijing 100875

We operated a p-type point contact high purity germanium(PPCGe)detector(CDEX-1B,1.008 kg)in the China Jinping Underground Laboratory(CJPL)for 500.3 days to search for neutrinoless double beta(0νββ)decay of^(76)Ge.A total of 504.3 kg⋅day effective exposure data was *** anti-coincidence and the multi/single-site event(MSE/SSE)discrimination methods were used to suppress the background in the energy region of interest(ROI,1989–2089 keV for this work)with a factor of 23.A background level of 0.33 counts/(keV⋅kg⋅yr)was *** lower limit on the half life of^(76)Ge 0νββdecay was constrained as T_(1/2)^(0ν)>1.0×10^(23)yr(90%C.L.),corresponding to the upper limits on the effective Majorana neutrino mass:<3.2–7.5 eV.

关键词： neutrinoless double beta decay CDEX point-contact germanium detector ^(76)Ge

MARCHING CUBES BASED FRONT TRACKING METHOD AND ITS APPLICATION TO SOME INTERFACE INSTABILITY PROBLEMS

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Journal of Hydrodynamics 2011年第5期23卷 580-588页

作者： WANG Jing-yi zou jian-feng ZHENG Yao ren An-lu 不详 Department of Engineering Mechanics School of Aeronautics and Astronautics Zhejiang University Hangzhou 310027 China

A front tracking method based on a marching cubes isosurface extractor, which is related filter generating isosurfaces from a structured point set, is provided to achieve sharp resolution for the simulation of non-diffusive interfacial flow. Compared with the traditional topology processing procedure, the current front tracking method is easier to be implemented and presents high performance in terms of computational resources. The numerical tests for 2-D highly-shearing flows and 3-D bubbles merging process are conducted to numerically examine the performance of the current methodology for tracking interfaces between two immiscible fluids The Rayleigh-Taylor （RT） and Richtmyer-Meshkov （RM） instability problems are successfully investigated with the present marching cubes based front tracking method.

关键词： interracial flow front tracking marching cubes bubbles merging process Rayleigh-Taylor (RT) instability Richtmyer- Meshkov (RM) instability

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垂直交叉双圆柱绕流数值模拟及涡结构分析

空气动力学学报 2005年第1期23卷 29-34页

作者：邓见任安禄邹建锋浙江大学力学系浙江杭州310027

用分块耦合方法数值模拟了垂直交叉双圆柱绕流 ,两圆柱间距为圆柱直径的 5倍 ,所取雷诺数为 2 0 0。在交叉结构的中心流场比较复杂 ,用λ2 方法准确地描述了其中的三维涡结构 ,发现上游圆柱规则的卡门涡街被下游圆柱截断成复杂的缠绕结... 详细信息

用分块耦合方法数值模拟了垂直交叉双圆柱绕流 ,两圆柱间距为圆柱直径的 5倍 ,所取雷诺数为 2 0 0。在交叉结构的中心流场比较复杂 ,用λ2 方法准确地描述了其中的三维涡结构 ,发现上游圆柱规则的卡门涡街被下游圆柱截断成复杂的缠绕结构。与串列双圆柱相比 ,垂直交叉双圆柱绕流上下圆柱的升阻力特性、Strouhal数等都呈现出许多不同的特点 ,下游圆柱升力振幅小于上游圆柱 ,阻力平均值大于上游圆柱。

关键词：圆柱绕流涡结构交叉柱相比卡门涡街耦合方法缠绕结构间距复杂阻力特性